porphyrize

例句：

1. 1.The paint on the wall has begun to porphyrize.
   墙上的油漆开始变黑了。
2. 2.The old books have started to discolor with age.
   旧书随着年龄开始褪色。
3. 3.The fabric has faded in the sun.
   这件衣物在阳光下已经失去了光泽。